cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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smp.c (19530B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  linux/arch/arm/kernel/smp.c
      4 *
      5 *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
      6 */
      7#include <linux/module.h>
      8#include <linux/delay.h>
      9#include <linux/init.h>
     10#include <linux/spinlock.h>
     11#include <linux/sched/mm.h>
     12#include <linux/sched/hotplug.h>
     13#include <linux/sched/task_stack.h>
     14#include <linux/interrupt.h>
     15#include <linux/cache.h>
     16#include <linux/profile.h>
     17#include <linux/errno.h>
     18#include <linux/mm.h>
     19#include <linux/err.h>
     20#include <linux/cpu.h>
     21#include <linux/seq_file.h>
     22#include <linux/irq.h>
     23#include <linux/nmi.h>
     24#include <linux/percpu.h>
     25#include <linux/clockchips.h>
     26#include <linux/completion.h>
     27#include <linux/cpufreq.h>
     28#include <linux/irq_work.h>
     29#include <linux/kernel_stat.h>
     30
     31#include <linux/atomic.h>
     32#include <asm/bugs.h>
     33#include <asm/smp.h>
     34#include <asm/cacheflush.h>
     35#include <asm/cpu.h>
     36#include <asm/cputype.h>
     37#include <asm/exception.h>
     38#include <asm/idmap.h>
     39#include <asm/topology.h>
     40#include <asm/mmu_context.h>
     41#include <asm/procinfo.h>
     42#include <asm/processor.h>
     43#include <asm/sections.h>
     44#include <asm/tlbflush.h>
     45#include <asm/ptrace.h>
     46#include <asm/smp_plat.h>
     47#include <asm/virt.h>
     48#include <asm/mach/arch.h>
     49#include <asm/mpu.h>
     50
     51#define CREATE_TRACE_POINTS
     52#include <trace/events/ipi.h>
     53
     54/*
     55 * as from 2.5, kernels no longer have an init_tasks structure
     56 * so we need some other way of telling a new secondary core
     57 * where to place its SVC stack
     58 */
     59struct secondary_data secondary_data;
     60
     61enum ipi_msg_type {
     62	IPI_WAKEUP,
     63	IPI_TIMER,
     64	IPI_RESCHEDULE,
     65	IPI_CALL_FUNC,
     66	IPI_CPU_STOP,
     67	IPI_IRQ_WORK,
     68	IPI_COMPLETION,
     69	NR_IPI,
     70	/*
     71	 * CPU_BACKTRACE is special and not included in NR_IPI
     72	 * or tracable with trace_ipi_*
     73	 */
     74	IPI_CPU_BACKTRACE = NR_IPI,
     75	/*
     76	 * SGI8-15 can be reserved by secure firmware, and thus may
     77	 * not be usable by the kernel. Please keep the above limited
     78	 * to at most 8 entries.
     79	 */
     80	MAX_IPI
     81};
     82
     83static int ipi_irq_base __read_mostly;
     84static int nr_ipi __read_mostly = NR_IPI;
     85static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly;
     86
     87static void ipi_setup(int cpu);
     88
     89static DECLARE_COMPLETION(cpu_running);
     90
     91static struct smp_operations smp_ops __ro_after_init;
     92
     93void __init smp_set_ops(const struct smp_operations *ops)
     94{
     95	if (ops)
     96		smp_ops = *ops;
     97};
     98
     99static unsigned long get_arch_pgd(pgd_t *pgd)
    100{
    101#ifdef CONFIG_ARM_LPAE
    102	return __phys_to_pfn(virt_to_phys(pgd));
    103#else
    104	return virt_to_phys(pgd);
    105#endif
    106}
    107
    108#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
    109static int secondary_biglittle_prepare(unsigned int cpu)
    110{
    111	if (!cpu_vtable[cpu])
    112		cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL);
    113
    114	return cpu_vtable[cpu] ? 0 : -ENOMEM;
    115}
    116
    117static void secondary_biglittle_init(void)
    118{
    119	init_proc_vtable(lookup_processor(read_cpuid_id())->proc);
    120}
    121#else
    122static int secondary_biglittle_prepare(unsigned int cpu)
    123{
    124	return 0;
    125}
    126
    127static void secondary_biglittle_init(void)
    128{
    129}
    130#endif
    131
    132int __cpu_up(unsigned int cpu, struct task_struct *idle)
    133{
    134	int ret;
    135
    136	if (!smp_ops.smp_boot_secondary)
    137		return -ENOSYS;
    138
    139	ret = secondary_biglittle_prepare(cpu);
    140	if (ret)
    141		return ret;
    142
    143	/*
    144	 * We need to tell the secondary core where to find
    145	 * its stack and the page tables.
    146	 */
    147	secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
    148#ifdef CONFIG_ARM_MPU
    149	secondary_data.mpu_rgn_info = &mpu_rgn_info;
    150#endif
    151
    152#ifdef CONFIG_MMU
    153	secondary_data.pgdir = virt_to_phys(idmap_pgd);
    154	secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir);
    155#endif
    156	secondary_data.task = idle;
    157	sync_cache_w(&secondary_data);
    158
    159	/*
    160	 * Now bring the CPU into our world.
    161	 */
    162	ret = smp_ops.smp_boot_secondary(cpu, idle);
    163	if (ret == 0) {
    164		/*
    165		 * CPU was successfully started, wait for it
    166		 * to come online or time out.
    167		 */
    168		wait_for_completion_timeout(&cpu_running,
    169						 msecs_to_jiffies(1000));
    170
    171		if (!cpu_online(cpu)) {
    172			pr_crit("CPU%u: failed to come online\n", cpu);
    173			ret = -EIO;
    174		}
    175	} else {
    176		pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
    177	}
    178
    179
    180	memset(&secondary_data, 0, sizeof(secondary_data));
    181	return ret;
    182}
    183
    184/* platform specific SMP operations */
    185void __init smp_init_cpus(void)
    186{
    187	if (smp_ops.smp_init_cpus)
    188		smp_ops.smp_init_cpus();
    189}
    190
    191int platform_can_secondary_boot(void)
    192{
    193	return !!smp_ops.smp_boot_secondary;
    194}
    195
    196int platform_can_cpu_hotplug(void)
    197{
    198#ifdef CONFIG_HOTPLUG_CPU
    199	if (smp_ops.cpu_kill)
    200		return 1;
    201#endif
    202
    203	return 0;
    204}
    205
    206#ifdef CONFIG_HOTPLUG_CPU
    207static int platform_cpu_kill(unsigned int cpu)
    208{
    209	if (smp_ops.cpu_kill)
    210		return smp_ops.cpu_kill(cpu);
    211	return 1;
    212}
    213
    214static int platform_cpu_disable(unsigned int cpu)
    215{
    216	if (smp_ops.cpu_disable)
    217		return smp_ops.cpu_disable(cpu);
    218
    219	return 0;
    220}
    221
    222int platform_can_hotplug_cpu(unsigned int cpu)
    223{
    224	/* cpu_die must be specified to support hotplug */
    225	if (!smp_ops.cpu_die)
    226		return 0;
    227
    228	if (smp_ops.cpu_can_disable)
    229		return smp_ops.cpu_can_disable(cpu);
    230
    231	/*
    232	 * By default, allow disabling all CPUs except the first one,
    233	 * since this is special on a lot of platforms, e.g. because
    234	 * of clock tick interrupts.
    235	 */
    236	return cpu != 0;
    237}
    238
    239static void ipi_teardown(int cpu)
    240{
    241	int i;
    242
    243	if (WARN_ON_ONCE(!ipi_irq_base))
    244		return;
    245
    246	for (i = 0; i < nr_ipi; i++)
    247		disable_percpu_irq(ipi_irq_base + i);
    248}
    249
    250/*
    251 * __cpu_disable runs on the processor to be shutdown.
    252 */
    253int __cpu_disable(void)
    254{
    255	unsigned int cpu = smp_processor_id();
    256	int ret;
    257
    258	ret = platform_cpu_disable(cpu);
    259	if (ret)
    260		return ret;
    261
    262#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
    263	remove_cpu_topology(cpu);
    264#endif
    265
    266	/*
    267	 * Take this CPU offline.  Once we clear this, we can't return,
    268	 * and we must not schedule until we're ready to give up the cpu.
    269	 */
    270	set_cpu_online(cpu, false);
    271	ipi_teardown(cpu);
    272
    273	/*
    274	 * OK - migrate IRQs away from this CPU
    275	 */
    276	irq_migrate_all_off_this_cpu();
    277
    278	/*
    279	 * Flush user cache and TLB mappings, and then remove this CPU
    280	 * from the vm mask set of all processes.
    281	 *
    282	 * Caches are flushed to the Level of Unification Inner Shareable
    283	 * to write-back dirty lines to unified caches shared by all CPUs.
    284	 */
    285	flush_cache_louis();
    286	local_flush_tlb_all();
    287
    288	return 0;
    289}
    290
    291/*
    292 * called on the thread which is asking for a CPU to be shutdown -
    293 * waits until shutdown has completed, or it is timed out.
    294 */
    295void __cpu_die(unsigned int cpu)
    296{
    297	if (!cpu_wait_death(cpu, 5)) {
    298		pr_err("CPU%u: cpu didn't die\n", cpu);
    299		return;
    300	}
    301	pr_debug("CPU%u: shutdown\n", cpu);
    302
    303	clear_tasks_mm_cpumask(cpu);
    304	/*
    305	 * platform_cpu_kill() is generally expected to do the powering off
    306	 * and/or cutting of clocks to the dying CPU.  Optionally, this may
    307	 * be done by the CPU which is dying in preference to supporting
    308	 * this call, but that means there is _no_ synchronisation between
    309	 * the requesting CPU and the dying CPU actually losing power.
    310	 */
    311	if (!platform_cpu_kill(cpu))
    312		pr_err("CPU%u: unable to kill\n", cpu);
    313}
    314
    315/*
    316 * Called from the idle thread for the CPU which has been shutdown.
    317 *
    318 * Note that we disable IRQs here, but do not re-enable them
    319 * before returning to the caller. This is also the behaviour
    320 * of the other hotplug-cpu capable cores, so presumably coming
    321 * out of idle fixes this.
    322 */
    323void arch_cpu_idle_dead(void)
    324{
    325	unsigned int cpu = smp_processor_id();
    326
    327	idle_task_exit();
    328
    329	local_irq_disable();
    330
    331	/*
    332	 * Flush the data out of the L1 cache for this CPU.  This must be
    333	 * before the completion to ensure that data is safely written out
    334	 * before platform_cpu_kill() gets called - which may disable
    335	 * *this* CPU and power down its cache.
    336	 */
    337	flush_cache_louis();
    338
    339	/*
    340	 * Tell __cpu_die() that this CPU is now safe to dispose of.  Once
    341	 * this returns, power and/or clocks can be removed at any point
    342	 * from this CPU and its cache by platform_cpu_kill().
    343	 */
    344	(void)cpu_report_death();
    345
    346	/*
    347	 * Ensure that the cache lines associated with that completion are
    348	 * written out.  This covers the case where _this_ CPU is doing the
    349	 * powering down, to ensure that the completion is visible to the
    350	 * CPU waiting for this one.
    351	 */
    352	flush_cache_louis();
    353
    354	/*
    355	 * The actual CPU shutdown procedure is at least platform (if not
    356	 * CPU) specific.  This may remove power, or it may simply spin.
    357	 *
    358	 * Platforms are generally expected *NOT* to return from this call,
    359	 * although there are some which do because they have no way to
    360	 * power down the CPU.  These platforms are the _only_ reason we
    361	 * have a return path which uses the fragment of assembly below.
    362	 *
    363	 * The return path should not be used for platforms which can
    364	 * power off the CPU.
    365	 */
    366	if (smp_ops.cpu_die)
    367		smp_ops.cpu_die(cpu);
    368
    369	pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n",
    370		cpu);
    371
    372	/*
    373	 * Do not return to the idle loop - jump back to the secondary
    374	 * cpu initialisation.  There's some initialisation which needs
    375	 * to be repeated to undo the effects of taking the CPU offline.
    376	 */
    377	__asm__("mov	sp, %0\n"
    378	"	mov	fp, #0\n"
    379	"	mov	r0, %1\n"
    380	"	b	secondary_start_kernel"
    381		:
    382		: "r" (task_stack_page(current) + THREAD_SIZE - 8),
    383		  "r" (current)
    384		: "r0");
    385}
    386#endif /* CONFIG_HOTPLUG_CPU */
    387
    388/*
    389 * Called by both boot and secondaries to move global data into
    390 * per-processor storage.
    391 */
    392static void smp_store_cpu_info(unsigned int cpuid)
    393{
    394	struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
    395
    396	cpu_info->loops_per_jiffy = loops_per_jiffy;
    397	cpu_info->cpuid = read_cpuid_id();
    398
    399	store_cpu_topology(cpuid);
    400	check_cpu_icache_size(cpuid);
    401}
    402
    403static void set_current(struct task_struct *cur)
    404{
    405	/* Set TPIDRURO */
    406	asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory");
    407}
    408
    409/*
    410 * This is the secondary CPU boot entry.  We're using this CPUs
    411 * idle thread stack, but a set of temporary page tables.
    412 */
    413asmlinkage void secondary_start_kernel(struct task_struct *task)
    414{
    415	struct mm_struct *mm = &init_mm;
    416	unsigned int cpu;
    417
    418	set_current(task);
    419
    420	secondary_biglittle_init();
    421
    422	/*
    423	 * The identity mapping is uncached (strongly ordered), so
    424	 * switch away from it before attempting any exclusive accesses.
    425	 */
    426	cpu_switch_mm(mm->pgd, mm);
    427	local_flush_bp_all();
    428	enter_lazy_tlb(mm, current);
    429	local_flush_tlb_all();
    430
    431	/*
    432	 * All kernel threads share the same mm context; grab a
    433	 * reference and switch to it.
    434	 */
    435	cpu = smp_processor_id();
    436	mmgrab(mm);
    437	current->active_mm = mm;
    438	cpumask_set_cpu(cpu, mm_cpumask(mm));
    439
    440	cpu_init();
    441
    442#ifndef CONFIG_MMU
    443	setup_vectors_base();
    444#endif
    445	pr_debug("CPU%u: Booted secondary processor\n", cpu);
    446
    447	trace_hardirqs_off();
    448
    449	/*
    450	 * Give the platform a chance to do its own initialisation.
    451	 */
    452	if (smp_ops.smp_secondary_init)
    453		smp_ops.smp_secondary_init(cpu);
    454
    455	notify_cpu_starting(cpu);
    456
    457	ipi_setup(cpu);
    458
    459	calibrate_delay();
    460
    461	smp_store_cpu_info(cpu);
    462
    463	/*
    464	 * OK, now it's safe to let the boot CPU continue.  Wait for
    465	 * the CPU migration code to notice that the CPU is online
    466	 * before we continue - which happens after __cpu_up returns.
    467	 */
    468	set_cpu_online(cpu, true);
    469
    470	check_other_bugs();
    471
    472	complete(&cpu_running);
    473
    474	local_irq_enable();
    475	local_fiq_enable();
    476	local_abt_enable();
    477
    478	/*
    479	 * OK, it's off to the idle thread for us
    480	 */
    481	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
    482}
    483
    484void __init smp_cpus_done(unsigned int max_cpus)
    485{
    486	int cpu;
    487	unsigned long bogosum = 0;
    488
    489	for_each_online_cpu(cpu)
    490		bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
    491
    492	printk(KERN_INFO "SMP: Total of %d processors activated "
    493	       "(%lu.%02lu BogoMIPS).\n",
    494	       num_online_cpus(),
    495	       bogosum / (500000/HZ),
    496	       (bogosum / (5000/HZ)) % 100);
    497
    498	hyp_mode_check();
    499}
    500
    501void __init smp_prepare_boot_cpu(void)
    502{
    503	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
    504}
    505
    506void __init smp_prepare_cpus(unsigned int max_cpus)
    507{
    508	unsigned int ncores = num_possible_cpus();
    509
    510	init_cpu_topology();
    511
    512	smp_store_cpu_info(smp_processor_id());
    513
    514	/*
    515	 * are we trying to boot more cores than exist?
    516	 */
    517	if (max_cpus > ncores)
    518		max_cpus = ncores;
    519	if (ncores > 1 && max_cpus) {
    520		/*
    521		 * Initialise the present map, which describes the set of CPUs
    522		 * actually populated at the present time. A platform should
    523		 * re-initialize the map in the platforms smp_prepare_cpus()
    524		 * if present != possible (e.g. physical hotplug).
    525		 */
    526		init_cpu_present(cpu_possible_mask);
    527
    528		/*
    529		 * Initialise the SCU if there are more than one CPU
    530		 * and let them know where to start.
    531		 */
    532		if (smp_ops.smp_prepare_cpus)
    533			smp_ops.smp_prepare_cpus(max_cpus);
    534	}
    535}
    536
    537static const char *ipi_types[NR_IPI] __tracepoint_string = {
    538	[IPI_WAKEUP]		= "CPU wakeup interrupts",
    539	[IPI_TIMER]		= "Timer broadcast interrupts",
    540	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
    541	[IPI_CALL_FUNC]		= "Function call interrupts",
    542	[IPI_CPU_STOP]		= "CPU stop interrupts",
    543	[IPI_IRQ_WORK]		= "IRQ work interrupts",
    544	[IPI_COMPLETION]	= "completion interrupts",
    545};
    546
    547static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
    548
    549void show_ipi_list(struct seq_file *p, int prec)
    550{
    551	unsigned int cpu, i;
    552
    553	for (i = 0; i < NR_IPI; i++) {
    554		if (!ipi_desc[i])
    555			continue;
    556
    557		seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
    558
    559		for_each_online_cpu(cpu)
    560			seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
    561
    562		seq_printf(p, " %s\n", ipi_types[i]);
    563	}
    564}
    565
    566void arch_send_call_function_ipi_mask(const struct cpumask *mask)
    567{
    568	smp_cross_call(mask, IPI_CALL_FUNC);
    569}
    570
    571void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
    572{
    573	smp_cross_call(mask, IPI_WAKEUP);
    574}
    575
    576void arch_send_call_function_single_ipi(int cpu)
    577{
    578	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
    579}
    580
    581#ifdef CONFIG_IRQ_WORK
    582void arch_irq_work_raise(void)
    583{
    584	if (arch_irq_work_has_interrupt())
    585		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
    586}
    587#endif
    588
    589#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
    590void tick_broadcast(const struct cpumask *mask)
    591{
    592	smp_cross_call(mask, IPI_TIMER);
    593}
    594#endif
    595
    596static DEFINE_RAW_SPINLOCK(stop_lock);
    597
    598/*
    599 * ipi_cpu_stop - handle IPI from smp_send_stop()
    600 */
    601static void ipi_cpu_stop(unsigned int cpu)
    602{
    603	if (system_state <= SYSTEM_RUNNING) {
    604		raw_spin_lock(&stop_lock);
    605		pr_crit("CPU%u: stopping\n", cpu);
    606		dump_stack();
    607		raw_spin_unlock(&stop_lock);
    608	}
    609
    610	set_cpu_online(cpu, false);
    611
    612	local_fiq_disable();
    613	local_irq_disable();
    614
    615	while (1) {
    616		cpu_relax();
    617		wfe();
    618	}
    619}
    620
    621static DEFINE_PER_CPU(struct completion *, cpu_completion);
    622
    623int register_ipi_completion(struct completion *completion, int cpu)
    624{
    625	per_cpu(cpu_completion, cpu) = completion;
    626	return IPI_COMPLETION;
    627}
    628
    629static void ipi_complete(unsigned int cpu)
    630{
    631	complete(per_cpu(cpu_completion, cpu));
    632}
    633
    634/*
    635 * Main handler for inter-processor interrupts
    636 */
    637static void do_handle_IPI(int ipinr)
    638{
    639	unsigned int cpu = smp_processor_id();
    640
    641	if ((unsigned)ipinr < NR_IPI)
    642		trace_ipi_entry_rcuidle(ipi_types[ipinr]);
    643
    644	switch (ipinr) {
    645	case IPI_WAKEUP:
    646		break;
    647
    648#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
    649	case IPI_TIMER:
    650		tick_receive_broadcast();
    651		break;
    652#endif
    653
    654	case IPI_RESCHEDULE:
    655		scheduler_ipi();
    656		break;
    657
    658	case IPI_CALL_FUNC:
    659		generic_smp_call_function_interrupt();
    660		break;
    661
    662	case IPI_CPU_STOP:
    663		ipi_cpu_stop(cpu);
    664		break;
    665
    666#ifdef CONFIG_IRQ_WORK
    667	case IPI_IRQ_WORK:
    668		irq_work_run();
    669		break;
    670#endif
    671
    672	case IPI_COMPLETION:
    673		ipi_complete(cpu);
    674		break;
    675
    676	case IPI_CPU_BACKTRACE:
    677		printk_deferred_enter();
    678		nmi_cpu_backtrace(get_irq_regs());
    679		printk_deferred_exit();
    680		break;
    681
    682	default:
    683		pr_crit("CPU%u: Unknown IPI message 0x%x\n",
    684		        cpu, ipinr);
    685		break;
    686	}
    687
    688	if ((unsigned)ipinr < NR_IPI)
    689		trace_ipi_exit_rcuidle(ipi_types[ipinr]);
    690}
    691
    692/* Legacy version, should go away once all irqchips have been converted */
    693void handle_IPI(int ipinr, struct pt_regs *regs)
    694{
    695	struct pt_regs *old_regs = set_irq_regs(regs);
    696
    697	irq_enter();
    698	do_handle_IPI(ipinr);
    699	irq_exit();
    700
    701	set_irq_regs(old_regs);
    702}
    703
    704static irqreturn_t ipi_handler(int irq, void *data)
    705{
    706	do_handle_IPI(irq - ipi_irq_base);
    707	return IRQ_HANDLED;
    708}
    709
    710static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
    711{
    712	trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
    713	__ipi_send_mask(ipi_desc[ipinr], target);
    714}
    715
    716static void ipi_setup(int cpu)
    717{
    718	int i;
    719
    720	if (WARN_ON_ONCE(!ipi_irq_base))
    721		return;
    722
    723	for (i = 0; i < nr_ipi; i++)
    724		enable_percpu_irq(ipi_irq_base + i, 0);
    725}
    726
    727void __init set_smp_ipi_range(int ipi_base, int n)
    728{
    729	int i;
    730
    731	WARN_ON(n < MAX_IPI);
    732	nr_ipi = min(n, MAX_IPI);
    733
    734	for (i = 0; i < nr_ipi; i++) {
    735		int err;
    736
    737		err = request_percpu_irq(ipi_base + i, ipi_handler,
    738					 "IPI", &irq_stat);
    739		WARN_ON(err);
    740
    741		ipi_desc[i] = irq_to_desc(ipi_base + i);
    742		irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
    743	}
    744
    745	ipi_irq_base = ipi_base;
    746
    747	/* Setup the boot CPU immediately */
    748	ipi_setup(smp_processor_id());
    749}
    750
    751void smp_send_reschedule(int cpu)
    752{
    753	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
    754}
    755
    756void smp_send_stop(void)
    757{
    758	unsigned long timeout;
    759	struct cpumask mask;
    760
    761	cpumask_copy(&mask, cpu_online_mask);
    762	cpumask_clear_cpu(smp_processor_id(), &mask);
    763	if (!cpumask_empty(&mask))
    764		smp_cross_call(&mask, IPI_CPU_STOP);
    765
    766	/* Wait up to one second for other CPUs to stop */
    767	timeout = USEC_PER_SEC;
    768	while (num_online_cpus() > 1 && timeout--)
    769		udelay(1);
    770
    771	if (num_online_cpus() > 1)
    772		pr_warn("SMP: failed to stop secondary CPUs\n");
    773}
    774
    775/* In case panic() and panic() called at the same time on CPU1 and CPU2,
    776 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop()
    777 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online,
    778 * kdump fails. So split out the panic_smp_self_stop() and add
    779 * set_cpu_online(smp_processor_id(), false).
    780 */
    781void panic_smp_self_stop(void)
    782{
    783	pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n",
    784	         smp_processor_id());
    785	set_cpu_online(smp_processor_id(), false);
    786	while (1)
    787		cpu_relax();
    788}
    789
    790/*
    791 * not supported here
    792 */
    793int setup_profiling_timer(unsigned int multiplier)
    794{
    795	return -EINVAL;
    796}
    797
    798#ifdef CONFIG_CPU_FREQ
    799
    800static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
    801static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
    802static unsigned long global_l_p_j_ref;
    803static unsigned long global_l_p_j_ref_freq;
    804
    805static int cpufreq_callback(struct notifier_block *nb,
    806					unsigned long val, void *data)
    807{
    808	struct cpufreq_freqs *freq = data;
    809	struct cpumask *cpus = freq->policy->cpus;
    810	int cpu, first = cpumask_first(cpus);
    811	unsigned int lpj;
    812
    813	if (freq->flags & CPUFREQ_CONST_LOOPS)
    814		return NOTIFY_OK;
    815
    816	if (!per_cpu(l_p_j_ref, first)) {
    817		for_each_cpu(cpu, cpus) {
    818			per_cpu(l_p_j_ref, cpu) =
    819				per_cpu(cpu_data, cpu).loops_per_jiffy;
    820			per_cpu(l_p_j_ref_freq, cpu) = freq->old;
    821		}
    822
    823		if (!global_l_p_j_ref) {
    824			global_l_p_j_ref = loops_per_jiffy;
    825			global_l_p_j_ref_freq = freq->old;
    826		}
    827	}
    828
    829	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
    830	    (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
    831		loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
    832						global_l_p_j_ref_freq,
    833						freq->new);
    834
    835		lpj = cpufreq_scale(per_cpu(l_p_j_ref, first),
    836				    per_cpu(l_p_j_ref_freq, first), freq->new);
    837		for_each_cpu(cpu, cpus)
    838			per_cpu(cpu_data, cpu).loops_per_jiffy = lpj;
    839	}
    840	return NOTIFY_OK;
    841}
    842
    843static struct notifier_block cpufreq_notifier = {
    844	.notifier_call  = cpufreq_callback,
    845};
    846
    847static int __init register_cpufreq_notifier(void)
    848{
    849	return cpufreq_register_notifier(&cpufreq_notifier,
    850						CPUFREQ_TRANSITION_NOTIFIER);
    851}
    852core_initcall(register_cpufreq_notifier);
    853
    854#endif
    855
    856static void raise_nmi(cpumask_t *mask)
    857{
    858	__ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
    859}
    860
    861void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
    862{
    863	nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi);
    864}